561220635565 has 4 divisors (see below), whose sum is σ = 673464762684. Its totient is φ = 448976508448.

The previous prime is 561220635557. The next prime is 561220635593. The reversal of 561220635565 is 565536022165.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 330884951076 + 230335684489 = 575226^2 + 479933^2 .

It is a cyclic number.

It is not a de Polignac number, because 561220635565 - 2³ = 561220635557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56122063552 + ... + 56122063561.

It is an arithmetic number, because the mean of its divisors is an integer number (168366190671).

Almost surely, 2^561220635565 is an apocalyptic number.

It is an amenable number.

561220635565 is a deficient number, since it is larger than the sum of its proper divisors (112244127119).

561220635565 is a wasteful number, since it uses less digits than its factorization.

561220635565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112244127118.

The product of its (nonzero) digits is 1620000, while the sum is 46.

The spelling of 561220635565 in words is "five hundred sixty-one billion, two hundred twenty million, six hundred thirty-five thousand, five hundred sixty-five".